Peritoneal dialysis catheters are of two general types: those designed for acute use (three days or less) and those for chronic use (over three days). Acute peritoneal dialysis catheters are straight, relatively rigid nylon or polyethylene catheters with numerous perforations or sideholes on the intraperitoneal portion. Chronic peritoneal dialysis catheters are constructed of soft materials like silicone rubber or polyurethane. The intraperitoneal portion may contain sideholes like the acute catheter, but may also have larger apertures for passage of the peritoneal fluid. Some chronic catheters have disks, beads or flanges at the parietal peritoneum to fix the catheter position. All have one or two extraperitoneal cuffs, which promote a local inflammatory response and tissue ingrowth, producing a fibrous plug to fix the catheter in position, prevent fluid leaks, and prevent bacterial migration around the catheter.
Some acute catheters are advanced into the abdomen with a pointed metal stylet inside; others have a tapered tip and are advanced into the abdomen over a guidewire. Acute catheters are fixed in place by suturing wings to the skin surface. Since there is no barrier to bacterial migration around the catheter, and because of the stiffness of the catheter, there is a significant risk of peritonitis, peritoneal irritation, and bowel perforation if the catheter is left in place for more than three days. For patients with acute renal failure, therapy usually is necessary for much more than three days. For these patients, safer access is provided by placing a chronic catheter at the start of dialysis therapy.
Historically, chronic peritoneal catheters have been made from a hydrophobic silicone polymer. However, such catheters suffer from a variety of problems such as infection of the biofilm on the catheter with attendant recurrent peritonitis, omental attachment to the catheter with resulting outflow obstruction, as well as mechanical failures leading to detachment of the catheter connectors.
Recently, curled peritoneal catheters have been made from a hydrophilic polyurethane. While this material of construction usually is smoother and stronger than a silicone polymer of comparable dimensions, such hydrophilic polyurethane catheters have not exhibited a reduced incidence of recurrent peritonitis, outflow obstruction or mechanical failures.